In the field of printers comprising a print unit provided with an inkjet printing head, numerous solutions and devices aimed at keeping the printing head constantly in an effective state, so that it is ready to print at any time, are known.
In particular, these solutions foresee both the use of devices adapted to protect and cover the area of the printing head nozzles during the relative periods of inactivity, and the execution of programmed cleaning cycles that work together with the protection devices to avoid the ink drying at the nozzles, so as to keep the inkjet printing head effective through time, i.e. always in a condition to print correctly.
In general, these cleaning cycles consist of the emission, against a receptacle, of a certain amount of ink in the form of drops by the inkjet printing head, and are carried out, in a programmed manner, after having parked the inkjet printing head in a certain cleaning position, outside of the printing area and usually provided at the side of the printing path along which the printing head translates back and forth during printing.
A printer of this type is known, for example, from European patent EP 1 080 909 A, and comprises in particular an inkjet printing head, provided with a plurality of nozzles and adapted to move back and forth along a printing area, and also a plurality of stations for the maintenance of the printing head arranged in the area at the side of the relative printing area.
The head is controlled so as to be arranged in a first position, in front of a corresponding hermetic sealing station, to couple with a protective cap, having the function of protecting and hermetically covering a front area of the printing head containing the nozzles, or else in a second position, in front of a corresponding cleaning station, to eject a certain amount of ink towards a vase-shaped receptacle during programmed cleaning cycles.
The Applicant has, however, observed that the solution proposed by this patent requires that the inkjet printing head be arranged in two distinct positions, outside the relative printing area, in order to carry out the necessary maintenance operations to keep it working effectively, i.e. to protect the printing head with the protective cap and to carry out the programmed cleaning cycles.
This solution necessarily involves a significant enlargement of the structure of the printer in the transversal direction, precisely so as to be able to house the inkjet printing head both in the protection position and in the cleaning position, to the side of the printing area.
U.S. Pat. No. 5,027,134 describes a service station for an inkjet printing head, having a cap that encloses and defines a cavity around the printing head when it is not in use, a basin to collect the ink discharged from the printing head and also a vent to prevent changes of pressure within the cavity, wherein within the cap capillary spaces, adapted to convey the liquid collected in the basin so as to move it away from the vent to prevent the vent from clogging, are formed.
When the printer starts up, or at selected times during printing, an algorithm activates the printing head to eject ink through the respective nozzles within the cap and the basin, so as to clean the nozzles and remove any ink clogging.
The Applicant has, nevertheless, observed that these solutions substantially complicate the manufacturing of the service station and of the relative protective cap, and also pose problems of evacuation of the cleaning ink that is ejected by the printing head inside the cavity defined by the protective cap, as well as problems of seal with respect to the outside of the cavity itself adjacent to the area of the nozzles.